Numerous types of flexible couplings are known for connecting two shafts in driving engagement. In one type, there is a thin flexible disc to which each shaft is joined by three, circumferentially-spaced, bolted or other rigid connections. Such connections impose strains on the disc in addition to those required for torque transmission and articulation. These strains are associated with additional stresses which reduce the torsional strength and fatigue life of the coupling.
The present invention provides a coupling in which shafts, for example, may be joined to a flexible element by connections with additional degrees of freedom so that the stresses and strains on the flexible element are reduced as compared with the above type of coupling and the life of the coupling thereby increased.
The present invention also increases, with respect to prior art couplings, the maximum articulation angle of the coupling as well as its maximum continuous running angle. Further, the invention provides a coupling in which the stresses are reduced so that the coupling may include a flexible element made from a relatively low cost plastic material, such as fiber-reinforced epoxy, polyamide or other resin, and which may be manufactured easily, for example by injection molding.
The coupling of the invention may also be used as a static coupling for connecting two non-rotating parts so that moments may be transmitted across the coupling.